This invention relates to a fluid pressure regulating valve mechanism; in particular, such a valve mechanism that substantially eliminates diaphragm flutter as can occur where a reciprocally movable diaphragm piston is acted upon by opposing fluid pressures. Such regulating-type valve mechanisms generally exhibit a proportional relationship between a control fluid pressure and an output fluid pressure. Such proportionality can be further varied by altering the structure of the diaphragm piston allowing for various modes of operation of the valve mechanism. Examples of such modes are: pressure intensification, pressure reduction, and a relay mode where a 1=1 ratio between control fluid pressure and output fluid pressure is maintained.
Typical regulating valve mechanisms have utilized an operating piston made of a metallic material and guided within a guide bore sealed by means of gaskets. This type of valve structure, however, has a disadvantage in that, the conventional sealing elements contribute a relatively high hysteresis regulating in a valve having undesirable delay characteristics. Still other regulating valves to date, have designed the piston as a diaphragm piston which avoids the problem of the high hysteresis delay condition but experiences a problem with diaphragm flutter. Such a valve mechanism is disclosed in the German Patent Publication DE-AS 15 23 493. The diaphragm piston of this valve mechanism consists of a first diaphragm which can be acted upon by the control fluid pressure, and a second diaphragm designed as a rolling membrane which can be acted upon by the output fluid pressure. The diaphragm piston serves the tripping of a combination inlet and outlet valve.
In case of a diaphragm piston consisting of a single diaphragm or of two diaphragms which act together with a valve, the problem surfaces that the oscillations of the diaphragm piston, generated by the pressure medium, are transmitted to the valve which can lead to a fluttering of the valve. The result may be an inaccurate pressure control and damage of the valve mechanism.